The invention relates to an elastomeric mixture, in particular based on EPM or EPDM, to which a thermally conductive component is added especially for the purpose of producing a hose for use as a solar collector and heat exchanger.
Now, two development works in this special field are introduced in the following in greater detail.
(A) Published document EP-A-0 864 823 describes a hose that is comprised of an inner layer made of elastomeric or plastic material, as well as of a thermally conductive reinforcement arranged on top of the inner layer and joined with the inner layer in an adhesive manner. The reinforcement is covered in this connection by an outer layer that consists of the same material as the inner layer. As an alternative, the reinforcement also can be dyed by means of a special coating, preferably with a black dye.
While suction and pressure hoses, for example pump hoses, hydraulic hoses and safety hoses for chemicals are necessarily provided with at least one reinforcing insert, hoses to be used as solar collectors and heat exchangers may be free of reinforcements as well.
Therefore, the development described above is necessarily intended for hoses with integrated reinforcements.
Furthermore, a drawback is that the reinforcement is comprised of only a limited proportion in terms of dimension with respect to the thickness of the wall of the hose. The consequence thereof is that the increased thermal conductivity connected with said measure does not cover the entire wall of the hose.
(B) A hose is introduced in the trade journal xe2x80x9cKGK Kautschuk Gummi Kunststoffexe2x80x9d, 50th Year, No. 11/97 (pages 766 to 775) that is comprised of an elastomer mixture to which a thermally conductive component is added, in particular under the aspect of aluminum powder.
However, in the manufacture of such hoses, the problem that had to be dealt with until now is that partial or complete demixing of the thermally conductive component was found to occur in the course of extrusion. However, a distribution of said component in the elastomer mixture that is as uniform as possible is a precondition for high thermal conductivity, on the one hand. On the other hand, extrusion (injection molding) is an important processing technology in the manufacture of hoses.